Staging is part of the diagnosis process. It tells you how widespread or advanced the melanoma is. It also helps doctors determine how to move forward with treatment and follow-up.
There are five stages of melanoma, starting at zero and going up to four. They are often written with the Roman numerals I, II, III, and IV.
Your doctor will assign a clinical stage to the cancer after your physical exam and the initial results from your other diagnostic tests and imaging.
The stage may be adjusted if you have additional tests or after surgery. This is called the pathologic stage.
Another name for stage 0 melanoma is melanoma in situ. This is the very beginning of the scale. It describes cancerous cells in the outermost layer of skin, called the epidermis.
Stage I and stage II melanoma describe invasive cancer that has grown below the epidermis to the next layer of skin, the dermis. It has not reached the lymph nodes.
Two major factors help determine the seriousness of stage I melanoma and stage II melanoma: Breslow depth and ulceration.
Breslow depth is a measurement that doctors use to describe the depth of an invasive melanoma in millimeters. It measures how far melanoma cells have reached below the surface of the skin. The thinner the melanoma, the better the chances for a cure.
Ulceration means that there is broken skin covering the melanoma. This breakage can be so small that it can only be seen under a microscope. Ulceration is an important factor in staging. A melanoma with ulceration may require more aggressive treatment than a melanoma of the same size without ulceration.
Melanoma is considered stage 1A when:
- the tumor is less than or equal to 1 millimeter thick in Breslow depth
Melanoma is considered stage IB when:
- the tumor is 1.1 to 2 millimeters thick in Breslow depth without ulceration
Melanoma is considered stage IIA when:
- the tumor is 1.1 to 2 millimeters thick in Breslow depth with ulceration
- the tumor is 2.1 to 4 millimeters thick in Breslow depth without ulceration
Melanoma is considered stage IIB when:
- the tumor is 2.1 to 4 millimeters thick in Breslow depth with ulceration
- the tumor is more than 4 millimeters in Breslow depth without ulceration
Melanoma is considered stage IIC when:
- the tumor is more than 4 millimeters thick in Breslow depth with ulceration
Stage III melanoma most often describes disease that has spread to the nearby lymph nodes. However, stage III disease may also refer to melanoma that has spread beyond the primary tumor but has not yet reached the nearest lymph nodes.
Stage III disease that has spread less than 2 centimeters from the primary tumor but has not yet reached the lymph nodes is called satellite melanoma. In-transit melanoma is the name given to disease that is more than 2 centimeters away from the primary melanoma but has not yet reached lymph nodes.
Stage IV is the most advanced stage of melanoma. The tumor may be any size, but it has spread to distant parts of the body beyond the skin and nearby lymph nodes, such as the liver, lungs, brain, bone, or gastrointestinal tract.
Melanoma may be stage IV when it is first diagnosed. Stage IV melanoma can also be recurrent melanoma. Recurrent means the melanoma has come back after treatment. The cancer may come back in the part of the body where it originally developed, in the lymph nodes, or in a distant part of the body.